Luis María Gil-Carcedo García

Del oído medio de las aves (Struthio camelus). Datos para la fisiología de la transmisión en sistemas de un único osículo en la cadena

Introduccion y objetivos La columela de las aves, citada frecuentemente en la literatura, no aparece descrita convenientemente. Pretendemos mostrar este elemento de transmission sonora precisando sus sistemas de anclaje y fijacion y detallando el musculo de que dispone. Material y metodo Realizamos una diseccion microscopica de especimenes de avestruz ( Struthio camelus ), y obtuvimos y procesamos imagenes de estos. Escogimos este animal por ser el ave con mayor tamano cefalico. Resultados Se describe la columela: el tripode oseo que se forma en su porcion externa (extracolumela), la forma conica de su porcion interna (estapedial), sus relaciones con la membrana timpanica y con la ventana oval. Mostramos sus medios de anclaje: ligamento posterior y ligamento anular. Relatamos las caracteristicas del musculo de la columela, sus inserciones y la potente vaina fibrosa que lo rodea. Conclusiones El oido medio de las aves es un modelo valido para la comprension de las caracteristicas mecanicas del oido humano, en el que se sustituye la cadena osicular por un solo elemento de transmision sonora. Denotamos una aparente paradoja: el musculo existente se inserta en la columela en un lugar proximo a la membrana timpanica, en vez de en la proximidad de la ventana oval.

Tubérculo de Zuckerkandl. Situación, forma y dimensiones

INTRODUCTION AND OBJECTIVE Although Zuckerkandls tubercle is not known by many head and neck surgeons, it is a fundamental surgical anatomical detail, already described in the nineteenth century. Its detection is of great importance as the reference in the search for the recurrent nerve and superior parathyroid gland. MATERIAL AND METHOD We designed a prospective study to analyse the posterolateral border of thyroid lobes, looking for this tubercle. We included 107 thyroidectomies performed by the same surgeon; 88 were total thyroidectomies (82.24%) and 19 hemithyroidectomies (17.75%), with dissection of a total of 195 thyroid lobes. Zuckerkandls tubercle should be sought by displacing the posterolateral margin of the thyroid lobes. RESULTS It was reliably detected in 155 thyroid lobes (79.48%). The mean tubercle dimensions were 11 mm transverse axis and 9 mm longitudinal axis. The shape of the Zuckerkandls tubercle was sessile (70.96%) or pedunculated (29.03%). In the 5.80% of cases, the Zuckerkandls tubercle distal end was bifid. We did not find a Zuckerkandls tubercle individualised as an ectopic thyroid (0.00%). Zuckerkandls tubercle was more frequent in the right thyroid lobe (P=.06). CONCLUSION Zuckerkandls tubercle is recognised by its location, shape and dimensions.

Nueva prótesis de maleovestibulopexia. Diseño y análisis experimental en un modelo computarizado 3D basado en elementos finitos

INTRODUCTION AND OBJECTIVE Many designs of prostheses are available for middle ear surgery. In this study we propose a design for a new prosthesis, which optimises mechanical performance in the human middle ear and improves some deficiencies in the prostheses currently available. Our objective was to design and assess the theoretical acoustic-mechanical behaviour of this new total ossicular replacement prosthesis. METHODS The design of this new prosthesis was based on an animal model (an iguana). For the modelling and mechanical analysis of the new prosthesis, we used a dynamic 3D computer model of the human middle ear, based on the finite elements method (FEM). RESULTS The new malleovestibulopexy prosthesis design demonstrates an acoustical-mechanical performance similar to that of the healthy human middle ear. This new design also has additional advantages, such as ease of implantation and stability in the middle ear. CONCLUSIONS This study shows that computer simulation can be used to design and optimise the vibroacoustic characteristics of middle ear implants and demonstrates the effectiveness of a new malleovestibulopexy prosthesis in reconstructing the ossicular chain.

The Avian Middle Ear (Struthio camelus). Data for the Physiology of Sound Transmission in Systems With a Single Ossicle in the Chain

Introduction and objetives The columella of birds, often cited in the literature, has yet to be adequately described. We aim to give an account of this transmission element, describing its anchoring systems and detailing the muscle associated to it. Material and method We performed microscopic dissection and obtained images of ostrich specimens ( Struthio camelus ), chosen because it is the bird with the largest head. Results We describe the columella: the osseous tripod formed on its external section (extracolumella), the conic shape of its inner section (stapedial), and links to the tympanic membrane and the oval window. We describe its anchoring system: posterior ligament and annular ligament. We conclude by describing the characteristics of the columella muscle, its insertions and the fibrous vein surrounding it. Conclusions The avian middle ear is a valid model for understanding the mechanical characteristics of the human ear repaired with total ossicular replacement prosthesis, ie replacement of the ossicular chain by a single element. We highlight an apparent contradiction: the existing muscle is inserted into the columella in an area close to the tympanic membrane rather than adjacent to the oval window.